Characterization of 12 Novel Microsatellite Markers of Sogatella furcifera (Hemiptera: Delphacidae) Identified From Next-Generation Sequence Data.

The white-backed planthopper, Sogatella furcifera (Horváth) (Hemiptera: Delphacidae), is a major pest of rice and has long-range migratory behavior in Asia. Microsatellite markers (simple sequence repeats) have been widely used to determine the origins and genetic diversity of insect pests. We identified novel microsatellite loci for S. furcifera samples collected from Laos, Vietnam, and three localities in Bangladesh from next-generation Roche 454 pyrosequencing data. Size polymorphism at 12 microsatellite loci was verified for 40 adult individuals collected from Shinan, South Korea. The average number of alleles per locus was 7.92. The mean values of observed (H(o)) and expected heterozygosities (H(E)) were 0.615 and 0.757, respectively. These new microsatellite markers will be a resource for future ecological genetic studies of S. furcifera samples across more broad geographic regions in Asia and may assist in estimations of genetic differentiation and gene flow among populations for implementation of more effective management strategies to control this serious rice pest.

Genetic structure of Lycorma delicatula (Hemiptera: Fulgoridae) populations in Korea: implication for invasion processes in heterogeneous landscapes.

Lycorma delicatula (White) was identified in 2004 as an invasive pest in South Korea, where it causes serious damage to vineyard crops. To investigate the population structure and dispersal pattern of L. delicatula in South Korea, we estimated the population genetic structure and gene flow among nine locations across the country using seven microsatellite markers. Although L. delicatula spread throughout most of its geographical range in South Korea within 5-7 years following invasion, its populations show evidence of genetic structuring across the range with a low but significant global F ST (genetic differentiation across all populations) of 0.0474. Bayesian-based clustering analysis indicates the presence of at least three genetically unique populations in South Korea, including populations in northeastern South Korea, which show a distinct genetic background. However, isolation by distance suggests that populations in South Korea have not yet reached genetic equilibrium. Estimates of the historical rate of gene flow (N e m) indicate that relatively high rates of flow have been maintained among populations within the western region, which may indicate recent range expansion. A population assignment test using the first-generation migrant detection method suggested that long-distance dispersal of L. delicatula may have occurred over large areas of South Korea. More complex dispersal patterns may have occurred during L. delicatula invasion of heterogeneous landscapes in South Korea.

Isolation and characterization of eight microsatellite loci from Lycorma delicatula (White) (Hemiptera: Fulgoridae) for population genetic analysis in Korea.

Lycorma delicatula (White) is native to China but is becoming an important insect pest in Korea. Polymorphic DNA markers like microsatellites are widely used for characterizing dispersal patterns and capacity of invasive insect pests which can contribute to designing effective management of the species. To facilitate such population genetic studies of L. delicatula in Korea, we isolated and characterized eight microsatellite loci for L. delicatula using a hybridization-biotin enrichment method. We further used these novel microsatellite loci to determine population genetic parameters for 33 L. delicatula specimens collected from Cheonan, South Korea where outbreaks of this species were first reported in Korea. The number of alleles per locus ranged from three to ten, with an average of 6.25. The mean expected (H (E)) and observed heterozygosities (H (O)) were 0.575 and 0.626, respectively. The eight loci showed no deviation from Hardy-Weinberg equilibrium according to the adjusted significance threshold (P = 0.00625), and there was no linkage disequilibrium between each pair of these eight markers. Bayesian cluster analysis using the program structure revealed no evidence of genetic structuring in L. delicatula samples from Cheonan. These new microsatellite markers will be widely applicable to future ecological genetic studies of L. delicatula, including assessment of the level of gene flow and genetic connectivity among populations that are necessary for effective management and monitoring of the species.